zink/lvp: mark 2d-arrays as cube-compatible
Turns out, OpenGL allows reinterpreting 2D array textures as cubemaps, so we need to always set the cube-compatible flag for them.
But there's some bugs in Lavapipe that needs to be fixed first, and we also need to validate some more stuff in Zink.
This fixes a piglit test on Lavapipe.
Edited by Erik Faye-Lund